First of all thanks in advance. I'm on the final push to finish the prep work for paint on my big window 59 Chevrolet Apache Fleetside. My plan is to get it all ready to be sprayed and then have a professional finish it. Plans are a 2-tone paint scheme at the body line. Corvette pewter metallic on the lower half and Tangelo pearl orange on the top and inside. I have recently been thinking of some type of pearl lime green instead of orange. Anyone have any color suggestions for the green?

Problem- I recently moved and the truck sat outside covered for about month. It has flash rust in several areas. Also the truck has had a five year build and the last primer was applied about 2 years ago. It needs to come off due to grease, dirt etc. as I finished the mechanicals of the truck. I have now taken the truck down (less bumpers, handles seat etc.) in preparation for the final paint.
Question-Should I use a 80 grit da sander and take all the primer down? I have applied Rage and Metal to Metal filler directly to metal areas that needed to be filled and over any replacement panels I welded. I then used Marhyde Single Stage Etching Primer to all exposed metal areas. (The truck was media blasted.) Then I used PCL Polyprimer over both the filler and the single stage etching primer.

Do I need to remove all the filler or only the primer, clean and re-shoot with primer?

Should I go to an epoxy primer this time. I was thinking that I should use the system recommend depending on the manufacture of the paint that I'm going to use. (HOK,PPG) Any problems with this?

I'm also going to Zero Rust the inside of the cab. Can I apply this directly over the newly sanded metal or do I need to lay down a fresh coat of primer.

I know that this is a long post, but I want to do it right. I have 5 years of my life invested in this truck. I will try and post some pictures.